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MAN page from openSUSE Leap 42 blas-man-3.5.0-9.1.noarch.rpm
chpmv.fSection: LAPACK (3) Updated: Fri Nov 4 2016 Index NAMEchpmv.f - SYNOPSIS Functions/Subroutines
subroutine CHPMV (UPLO, N, ALPHA, AP, X, INCX, BETA, Y, INCY)
CHPMV
Function/Subroutine Documentation subroutine CHPMV (character UPLO, integer N, complex ALPHA, complex, dimension(*) AP, complex, dimension(*) X, integer INCX, complex BETA, complex, dimension(*) Y, integer INCY)CHPMV Purpose: CHPMV performs the matrix-vector operation y := alpha*A*x + beta*y, where alpha and beta are scalars, x and y are n element vectors and A is an n by n hermitian matrix, supplied in packed form.
Parameters: - UPLO
UPLO is CHARACTER*1 On entry, UPLO specifies whether the upper or lower triangular part of the matrix A is supplied in the packed array AP as follows: UPLO = 'U' or 'u' The upper triangular part of A is supplied in AP. UPLO = 'L' or 'l' The lower triangular part of A is supplied in AP.
N
N is INTEGER On entry, N specifies the order of the matrix A. N must be at least zero.
ALPHA
ALPHA is COMPLEX On entry, ALPHA specifies the scalar alpha.
AP
AP is COMPLEX array of DIMENSION at least ( ( n*( n + 1 ) )/2 ). Before entry with UPLO = 'U' or 'u', the array AP must contain the upper triangular part of the hermitian matrix packed sequentially, column by column, so that AP( 1 ) contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 1, 2 ) and a( 2, 2 ) respectively, and so on. Before entry with UPLO = 'L' or 'l', the array AP must contain the lower triangular part of the hermitian matrix packed sequentially, column by column, so that AP( 1 ) contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 2, 1 ) and a( 3, 1 ) respectively, and so on. Note that the imaginary parts of the diagonal elements need not be set and are assumed to be zero.
X
X is COMPLEX array of dimension at least ( 1 + ( n - 1 )*abs( INCX ) ). Before entry, the incremented array X must contain the n element vector x.
INCX
INCX is INTEGER On entry, INCX specifies the increment for the elements of X. INCX must not be zero.
BETA
BETA is COMPLEX On entry, BETA specifies the scalar beta. When BETA is supplied as zero then Y need not be set on input.
Y
Y is COMPLEX array of dimension at least ( 1 + ( n - 1 )*abs( INCY ) ). Before entry, the incremented array Y must contain the n element vector y. On exit, Y is overwritten by the updated vector y.
INCY
INCY is INTEGER On entry, INCY specifies the increment for the elements of Y. INCY must not be zero.
Author: - Univ. of Tennessee
Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd.
Date: - November 2011
Further Details: Level 2 Blas routine. The vector and matrix arguments are not referenced when N = 0, or M = 0 -- Written on 22-October-1986. Jack Dongarra, Argonne National Lab. Jeremy Du Croz, Nag Central Office. Sven Hammarling, Nag Central Office. Richard Hanson, Sandia National Labs.
Definition at line 151 of file chpmv.f. 151 *152 * -- Reference BLAS level2 routine (version 3.4.0) --153 * -- Reference BLAS is a software package provided by Univ. of Tennessee, --154 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--155 * November 2011156 *157 * .. Scalar Arguments ..158 COMPLEX alpha,beta159 INTEGER incx,incy,n160 CHARACTER uplo161 * ..162 * .. Array Arguments ..163 COMPLEX ap(*),x(*),y(*)164 * ..165 *166 * =====================================================================167 *168 * .. Parameters ..169 COMPLEX one170 parameter(one= (1.0e+0,0.0e+0))171 COMPLEX zero172 parameter(zero= (0.0e+0,0.0e+0))173 * ..174 * .. Local Scalars ..175 COMPLEX temp1,temp2176 INTEGER i,info,ix,iy,j,jx,jy,k,kk,kx,ky177 * ..178 * .. External Functions ..179 LOGICAL lsame180 EXTERNAL lsame181 * ..182 * .. External Subroutines ..183 EXTERNAL xerbla184 * ..185 * .. Intrinsic Functions ..186 INTRINSIC conjg,real187 * ..188 *189 * Test the input parameters.190 *191 info = 0192 IF (.NOT.lsame(uplo,'U') .AND. .NOT.lsame(uplo,'L')) THEN193 info = 1194 ELSE IF (n.LT.0) THEN195 info = 2196 ELSE IF (incx.EQ.0) THEN197 info = 6198 ELSE IF (incy.EQ.0) THEN199 info = 9200 END IF201 IF (info.NE.0) THEN202 CALL xerbla('CHPMV ',info)203 RETURN204 END IF205 *206 * Quick return if possible.207 *208 IF ((n.EQ.0) .OR. ((alpha.EQ.zero).AND. (beta.EQ.one))) RETURN209 *210 * Set up the start points in X and Y.211 *212 IF (incx.GT.0) THEN213 kx = 1214 ELSE215 kx = 1 - (n-1)*incx216 END IF217 IF (incy.GT.0) THEN218 ky = 1219 ELSE220 ky = 1 - (n-1)*incy221 END IF222 *223 * Start the operations. In this version the elements of the array AP224 * are accessed sequentially with one pass through AP.225 *226 * First form y := beta*y.227 *228 IF (beta.NE.one) THEN229 IF (incy.EQ.1) THEN230 IF (beta.EQ.zero) THEN231 DO 10 i = 1,n232 y(i) = zero233 10 CONTINUE234 ELSE235 DO 20 i = 1,n236 y(i) = beta*y(i)237 20 CONTINUE238 END IF239 ELSE240 iy = ky241 IF (beta.EQ.zero) THEN242 DO 30 i = 1,n243 y(iy) = zero244 iy = iy + incy245 30 CONTINUE246 ELSE247 DO 40 i = 1,n248 y(iy) = beta*y(iy)249 iy = iy + incy250 40 CONTINUE251 END IF252 END IF253 END IF254 IF (alpha.EQ.zero) RETURN255 kk = 1256 IF (lsame(uplo,'U')) THEN257 *258 * Form y when AP contains the upper triangle.259 *260 IF ((incx.EQ.1) .AND. (incy.EQ.1)) THEN261 DO 60 j = 1,n262 temp1 = alpha*x(j)263 temp2 = zero264 k = kk265 DO 50 i = 1,j - 1266 y(i) = y(i) + temp1*ap(k)267 temp2 = temp2 + conjg(ap(k))*x(i)268 k = k + 1269 50 CONTINUE270 y(j) = y(j) + temp1*REAL(AP(KK+J-1)) + alpha*temp2271 kk = kk + j272 60 CONTINUE273 ELSE274 jx = kx275 jy = ky276 DO 80 j = 1,n277 temp1 = alpha*x(jx)278 temp2 = zero279 ix = kx280 iy = ky281 DO 70 k = kk,kk + j - 2282 y(iy) = y(iy) + temp1*ap(k)283 temp2 = temp2 + conjg(ap(k))*x(ix)284 ix = ix + incx285 iy = iy + incy286 70 CONTINUE287 y(jy) = y(jy) + temp1*REAL(AP(KK+J-1)) + alpha*temp2288 jx = jx + incx289 jy = jy + incy290 kk = kk + j291 80 CONTINUE292 END IF293 ELSE294 *295 * Form y when AP contains the lower triangle.296 *297 IF ((incx.EQ.1) .AND. (incy.EQ.1)) THEN298 DO 100 j = 1,n299 temp1 = alpha*x(j)300 temp2 = zero301 y(j) = y(j) + temp1*REAL(ap(kk))302 k = kk + 1303 DO 90 i = j + 1,n304 y(i) = y(i) + temp1*ap(k)305 temp2 = temp2 + conjg(ap(k))*x(i)306 k = k + 1307 90 CONTINUE308 y(j) = y(j) + alpha*temp2309 kk = kk + (n-j+1)310 100 CONTINUE311 ELSE312 jx = kx313 jy = ky314 DO 120 j = 1,n315 temp1 = alpha*x(jx)316 temp2 = zero317 y(jy) = y(jy) + temp1*REAL(ap(kk))318 ix = jx319 iy = jy320 DO 110 k = kk + 1,kk + n - j321 ix = ix + incx322 iy = iy + incy323 y(iy) = y(iy) + temp1*ap(k)324 temp2 = temp2 + conjg(ap(k))*x(ix)325 110 CONTINUE326 y(jy) = y(jy) + alpha*temp2327 jx = jx + incx328 jy = jy + incy329 kk = kk + (n-j+1)330 120 CONTINUE331 END IF332 END IF333 *334 RETURN335 *336 * End of CHPMV .337 * AuthorGenerated automatically by Doxygen for LAPACK from the source code.
Index- NAME
- SYNOPSIS
- Functions/Subroutines
- Function/Subroutine Documentation
- subroutine CHPMV (character UPLO, integer N, complex ALPHA, complex, dimension(*) AP, complex, dimension(*) X, integer INCX, complex BETA, complex, dimension(*) Y, integer INCY)
- Author
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